An optical semiconductor package includes a plurality of leads and resin for holding the leads. The leads are classified as a lead for mounting an optical semiconductor element and at least one lead that acts as an external terminal and is electrically connected to the terminals of the mounted optical semiconductor element. The optical semiconductor package may include a reflector that surrounds at least the mounting region of the optical semiconductor element.
The reflector may be made of the same resin as the resin for holding the leads or a different resin. The reflector is provided to reflect light emitted from the optical semiconductor element so as to improve the luminous efficiency of light emitted from an optical semiconductor device. Hence, at least the reflector is generally made of a thermoplastic resin having a high reflectivity of light (for example, see Patent Literature 1).
Conventionally, optical semiconductor packages have been produced by injection molding because a thermoplastic resin has a high viscosity and low flowability. In this case, for example, a mold is set at about 150° C. to 200° C. and resin is set at about 300° C. to 330° C. before injection. The resin is injected into the mold and then is cured by cooling. The thermoplastic resin has high water absorption of about 3% to 1% and thus the thermoplastic resin containing absorbed water is hydrolyzed during injection molding. For this reason, the thermoplastic resin is dried before injection molding.